Diffusion-weighted magnetic resonance imaging of parotid glands before and after abatacept therapy in patients with Sjögren’s syndrome associated with rheumatoid arthritis: Utility to evaluate and predict response to treatment

<b>Objective:</b> To compare parotid diffusion-weighted images (DWIs) taken before and after abatacept therapy in patients with Sjögren’s syndrome (SS) associated with rheumatoid arthritis (RA) and to examine the utility in evaluation and prediction of response to therapy. <b>Methods:</b> DWIs of the parotid glands taken at baseline and 52 weeks after initiation of abatacept were analyzed in nine SS patients with RA using relative standard deviation (RSD) of the entire glands and signal intensity ratio (SIR) within the residual parenchyma. The correlation between changes in RSD and SIR and changes in salivary secretion based on Saxon’s test was examined. Furthermore, baseline characteristics were compared in patients with increased and decreased salivary secretion after treatment. The predictive power of the parameter at baseline was examined using receiver operating characteristic (ROC) analysis. <b>Results:</b> Abatacept improved salivary secretion from 2076 ± 1535 at baseline to 2857 ± 1431 mg/2 min at 52 weeks (<i>n</i> = 9, <i>p</i> = .05). Increase of salivary secretion was significantly higher in patients with decreased RSD (<i>n</i> = 6) than increased RSD (<i>n</i> = 3) (1241 ± 713, –137 ± 142 mg/2 min, <i>p</i> = .02). The increase and decrease in RSD completely accorded with those of salivary secretion. Furthermore, SIR was the only parameter that was significantly different between patients with posttreatment increase and decrease in salivary secretion (<i>p</i> = .04). ROC analysis showed the sensitivity and specificity of SIR at baseline of ≥13.0 × 10⁻² for the prediction of the response to abatacept were 75.0% and 83.3%, respectively. <b>Conclusions:</b> Parotid DWI seems to be useful for evaluating and predicting the response in salivary secretion to abatacept in SS patients with RA.

【研究目的】对比伴类风湿关节炎（Rheumatoid Arthritis, RA）的干燥综合征（Sjögren’s syndrome, SS）患者接受阿巴西普（abatacept）治疗前后的腮腺弥散加权成像（Diffusion-Weighted Images, DWI），并探讨其在评估与预测治疗应答中的应用价值。【研究方法】纳入9例伴RA的SS患者，对其基线期及阿巴西普治疗启动后52周的腮腺DWI进行分析，采用全腮腺相对标准偏差（Relative Standard Deviation, RSD）与残留腺体实质内的信号强度比（Signal Intensity Ratio, SIR）作为量化指标。基于萨克斯试验（Saxon’s test）结果，分析RSD、SIR的变化值与唾液分泌量变化之间的相关性；对比治疗后唾液分泌量升高与降低两组患者的基线特征；并通过受试者工作特征（Receiver Operating Characteristic, ROC）分析评估基线期参数的预测效能。【研究结果】阿巴西普治疗可使患者唾液分泌量从基线期的2076±1535 mg/2min提升至52周时的2857±1431 mg/2min（n=9，p=0.05）。RSD降低的患者（n=6）唾液分泌量增幅显著高于RSD升高的患者（n=3），分别为1241±713 mg/2min与-137±142 mg/2min（p=0.02）；且RSD的变化趋势与唾液分泌量的变化完全一致。此外，SIR是唯一可区分治疗后唾液分泌量升高与降低患者的参数（p=0.04）。ROC分析显示，当基线期SIR≥13.0×10^-2时，其预测阿巴西普治疗应答的灵敏度为75.0%，特异度为83.3%。【研究结论】腮腺DWI或可用于评估并预测伴RA的SS患者对阿巴西普治疗的唾液分泌应答效果。